Bat House Forum

[Joe Spencer]

Some have already seen this but it is a good news(potential identification) bad news (can't stop it as of yet) situation. If I read this correctly this could have been transmitted to bats by people or another animal. Correct me if I misinterpreted:

http://www.npr.org/templates/story/stor ... 11&sc=emaf

[Erik]

Some additional information:

The article says:

Now, researchers have identified the mold they consider a possible cause of the disease, reporting their findings Thursday in the online edition of the journal Science. It's a fragile, unusual form of Geomyces fungi, which usually live in cold places such as Antarctica, says David Blehert, lead author of the study. He's head of diagnostic microbiology at the U.S. Geological Survey's National Wildlife Health Center in Madison, Wis.

Blehert can't say for certain that the fungus is killing the bats. "Fungi usually don't kill otherwise healthy animals all on their own," he explains. He says the infection may make a bat wake up too often during hibernation, so that it burns up its reserves of fat too quickly.

The fungus they discovered is a possible cause but that is not certain at all. There is also the possibility that an unknown cause (infection, pathogen, toxic) causes a disease or condition that makes the bat very vulnerable for this fungus. That the fungus is new to science makes it suspicious as a the infection that is responsible for the mortality of bats.

Very good information on WNS, the Fungus and on all the questions to be answered:

• White-nose syndrome : science strategy meeting, June 10, 2008. Albany NY synopsis.
• Blehert, David S . 2008. Bat White-Nose Syndrome: An Emerging Fungal Pathogen? In: Sciencecpress, 30 October 2008.

For the Dutch Mammal Society (VZZ) I have just finished some study on WNS. After WNS was also in the news here (in april) a bat researcher sent me a picture of bat found in the Netherlands in winter 2005-2006 with a condition looking very similar as the WNS-symptoms. In the same winter and following winters sightings of bats with possible White Nose Syndrome were found in the same hibernaculum, but also in Belgium, France and Germany. It is limited to just a few bats and there is obvious mortality or raised activity during hibernation. Because of that, there was not much attention to it, until the devastating news about the bats in North East States reached us.
We are now working together with several bat research societies and also with David Blehert and Allan Hicks. Of course we hope WNS is not going to be a world wide disaster for bats. When the fungus we observed is indeed the same as in WNS disease this is interesting for the research on WNS in the states. If high mortality is not going to happen here, it may also may be a clue that there are other factors that in the mortality of bats in the States.

Greetings,
Erik

[GFox]

Here is a WNS page that seems to be updated regularly:

http://www.caves.org/WNS/WNS%20Info.htm

[GFox]

Here is a link summarizing some WNS research.

http://www.caves.org/WNS/WNS2009research.pdf

[Joe Spencer]

Nice Chart in there showing the prominence of WNS in myotis. It is not surprising though considering this species hibernates in caves, mines etc in great numbers and is far more likely to infect another bat. The fact that big brown bats have adapted like inner city pigeons and will choose to hibernate in buildings and places other than caves and mines has likely helped to keep the WNS cases for this bat far lower. Since WNS is spreading quickly to other states, more resources need to be devoted to this issue. Ironically and sadly if this were a bird issue and the same number of species were dying in great numbers, it is likely that the audubon society would be on it quickly and it would be all over the news garnering support. Thanks again for this update!

[ShenandoahJoe]

What we need is for someone to invent a winter bat house. No way is a fungus going to climb up a fifteen-foot pole.

Joe

[Joe Spencer]

Joe, ironically Richathome heated a bat house and kept a bat during the winter here: http://www.bathouseforum.org/forum/viewtopic.php?f=3&t=621&p=3494&hilit=heat+tape#p3494

[Dave Miller]

It is my understanding that bats in torpor need an environment with cool (but not freezing) stable temperatures, and stable, relatively high humidity. It is the humidity requirement that sends them into caves and mines (and attics in moist temperate climates) in the fall. Thus a heated bat house might meet the temperature requirements when it is cold out, but may not meet the humidity requirement.

If during torpor the humidity is too low for too long, the bats will die of dehydration!

[Joe Spencer]

Agreed Dave, that is why I decided not to try it in NewEngland where our winters have extremely low humidity. If one could rig a bat house above for the foraging season and have a channel to the right area of a basement (placement critical) then it might work. Since there are so many variables and requirements, it would be difficult to get it just right and you risk harming the bat. Excerpt on BB hibernation: "Big brown bats seldom move more than 120 km between nursery and hibernation sites. Some individuals may use the same site as a nursery roost and a hibernaculum; however, this is unusual. Hibernacula are characterized by low humidity, variable temperature and often, considerable air movement. If the temperature in the hibernaculum drops below -4°C, big brown bats will arouse themselves from torpor and seek a warmer site. This may be one of the reasons you never have little browns overwintering in buildings and homes. They require 90-100% humidity. In my home on a dry 20 degree winter day I have had humidity levels upstairs (without my humidifier on) at 28% and 40% in the basement. Mark Kiser (formerly of BCI) mentions below that big browns roost at cave entrances where it is cooler and has less humidity. It certainly doesn't imply they need little humidity. The big brown's I have encountered overwintering in homes have usually been in basements where it is far more humid. One was found in the upper area of the basement near the house sill. That would make a lot of sense since it was far colder there than the basement which was 50 degrees and the bat found a place where temperature and humidity best met its needs! I have also found them in attics hibernating but it is far less likely where I live. It is likely mainly due to the minimum humidity levels required. Big browns are hardier and more tolerant than little browns when it comes to winter humidity level requirements but I agree unless your willing to run a really reliable somewhat sophisticated hibernacula experiment, it is best not to risk endangering big browns.

MY response to richathome who tried to keep a bat overwinter original post concurs with you Dave:

Awesome work Rich! Looking forward to your data logging and feedback on your occupant. Based on below, your temperature may just be good enough. The only thing that we can't provide and must consider is the natural amount of humidity that exists in caves and mines which assists in keeping bats hydrated during their hibernation. But since big brown's often hibernate in buildings/homes they may tolerate less humidity than other species which may need more.

MARK Kiser formerly of BCI

Little brown bats and big brown bats need stable temperatures in their winter roost sites. Little brown bats like temps. near the low 40s F and humidity near 100 %.

Big brown bats often roost near the entrance and thus can tolerate even cooler temps.

Don't know if there is a minium suitable size, but roost configuration will play a big role in how stable the air temps are, whether the chamber traps cold air or releases it. There's a diagram in the Bats and Mines Handbook that shows several cave/mine configurations, and it describes how the passageway layouts dictate how warm air and cool air move (enters, exits, collects) in summer vs. winter.

Hope this helps.

Mark

Good post Dave!

[Dave Miller]

I did not know about the different requirements of little browns and big browns. Reading the posts here I wonder if big browns prefer more air movement and less humidity than little browns, in bat houses as well as hibernacula?

[ShenandoahJoe]

It almost sounds like we're discussing wine cellars here. If I ever get around to building one, should I include a second, very small door?

Joe

[Joe Spencer]

It almost sounds like we're discussing wine cellars here. If I ever get around to building one, should I include a second, very small door?

Joe

If something were deep enough and there was enough air movement it might be fine. The only thing I would be concerned about is disturbance. In a cave which had a major outbreak of WNS there were numerous visitors. Bats evidently and clearly need their quiet and privacy during these approximately 6 months of hibernation. Big browns have been known to hibernate in road culverts where they're below the frost level and where they likely have air movement. Joe, check out the progress of this man made bat cave which to me is an inverse swimming pool construction/installation:

INSTALLATION:
http://www.batcon.org/index.php/education/article-and-information/bats-magazine.html?task=viewArticle&magArticleID=833

SUCCESSFUL AFTERMATH also ironically mentioning WINE CELLAR: http://www.bambergerranch.org/facilities/bats.phtml

[Joe Spencer]

I did not know about the different requirements of little browns and big browns. Reading the posts here I wonder if big browns prefer more air movement and less humidity than little browns, in bat houses as well as hibernacula?

I wonder that too Dave! Maybe we'll find out more through their preferences and behavior. Since WNS has decimated those bats which require/prefer 90-100% humidity and biologists have noted that the WNS fungi thrive in these cold humid environments, it is no wonder that big brown bats preference for lower humidity locations may have spared many. Coupled with their flexible hibernacula choices they would be less exposed to this dreaded affliction and their numbers should remain far stronger than myotis. I am so saddened by this because for years I have had about a 10-1 ratio of big browns to little browns with me having mostly big browns. I wonder what WNS will eventually do to sites like Terry Lobdell who has a lot of little browns. We'll look forward to Terry's headcount and feedback. I sure hope this doesn't spread further but it is likely it will until they can determine the root cause no?

[Joe Spencer]

Here is an up to date site with great graphics on WNS: http://www.fort.usgs.gov/WNS/

[kent borcherding]

I have observed small colonies of little brown bats hibernating in smaller wine cellars -- 20ft x 75 ft.
The bats entered and exited through the ventalation pipe.

Also have observed eastern pips hibernating in older closed beer breweries limestone cellars.

Perhaps a possible source of fungus could have been from new or exotic plants being grown in some caves or coolers that bats were hibernating and carried to other sites by the bats.

Possibly fungus cou;d have began growing on wood shelving or crates from native or exotic woods in some mines or caves that people may have began to store fruits or vegetables in and carried by the bats to other hibernaculums.